I don't know so much about the forwards, but my Lions starting 9-15 would be:
Hogg
Brown
O'Driscoll/Tuilagi
Roberts
North
Sexton
Phillips
I think O'Driscoll can still give you a good hour, Tuilagi coming from the bench. Halfpenny had a great 6 Nations, but Hogg has that little bit more creative spark. Sexton beats Farrell for the fly half because I think he has more ability to control the game than Farrell, but I think this will come to Farrell with experience. North has to start, Cuthbert or Brown is a close call, as is scrum half.
The only Scots I can see going are Hogg, Murray, Hamilton, Beattie and Gray if fit, Laidlaw, Visser and Kelly Brown will probably miss out as the competition is so high in those positions.